Electrically-heated hand-stamp



(No Model.)

J. B. VBNK'ER. A BLECTRIALLY HEATBD HAND STAMP.

No. 484,574. Patented Oct. 18, 1892.

UNITED STATES PATENT OFFICE.

JOHN BARNEY VENKER, OF ST. LOUIS, MISSOURI.

ELECTRlCALLY-H EATED HAN D-STAM P.

SPECIFICATION forming part of Letters Patent No. 484,574, dated October 18, 1892.

Application filed December 11, 1891. Serial No. 414,696. (No model.)

.To all whom t may concern,.-

Be it known that I, JOHN BARNEY VENKER, of the city of St. Louis and State of Missouri, have invented certain newand useful Improvements in Electrically-I-Ieated Stamp-Presses, of which the following is a full, clear, and eX- act description, reference being had to the accompanying drawings, forming a part hereof.

My invention relates to a new and improved electrically-heated stamp-press; and it consists in the novel features and combination of parts hereinafter set forth and claimed.

In the drawings, Figure 1 is a broken side elevation of a machine embodying my invention. Fig. 2 is a front elevation of same. Fig. 3 is a top plan view of one of the heating and pressure plates which I employ in carrying out my invention, showing the arrangement of the electric resistance thereon. Fig. 4 is a detail cross-section taken through the movable upper pressure and heating section of the apparatus.

In order to thoroughly understand the nature of my invention and the particular uses thereof, it will be well to here state briefly the manner in which rubber stamps have ordinarily been made. A block of composition is employed, upon the surface of which is imprinted the words or characters desired, and a sheet of rubber, from which the stamp is to be formed, is placed upon said imprinted surface of the composition,and the whole in this position placed in a press. The plates which come in contact with both the sheet of rubber and the composition have heretofore been heated in various complicated and costly manners, such as by steam or dame applied to said plates.

The object of my invention is to dispense with such costly and complicated heating devices and accomplish the heating or vulcanization of the rubber by special electrical appliances.

Referring to the drawings, 1 represents two supports or legs, the lower ends of which rest upon or are secured to the iioorin any suitable manner. Upon the upper portions of said supports a bed-plate is mounted, the same being indicated by the numeral 2. On the upper surface of bed-plate 2 is secured a pressing mechanism 3, consisting of a yoke 4, the

lower ends of which are secured to said base or bed plate, and ascrew 5, mounted vertically in the median portion of said yoke. An operating bar or handle 6 is mounted on the upper end of said screw and two balls 7 mounted on opposite ends of said bar.

Formed in the upper portion of the bedplate 2 is a depression S, and located in said depression is a comparatively-thick sheet of asbestus 9, which insulates the bed-plate from' the heating and pressure plate l0 both thermally and electrically to a proper degree.

To the lower end of the screw 5 is connected loosely a metallic plate l1, which is adapted to be moved toward and from said bed-plate of the machine by the turning of said screw. Upon the under surface of the plate 11 a sheet of asbestus 12, similar in thickness to the before-mentioned sheet 9, or a sheet of insulation of any kind which will withstand the intense heat to which it is subjected is secured, and upon the under surface of said sheet of insulation 12 is secured by means of suitable fastenings-such as bolts or rivets--a heating and pressure plate 13, similar in dimensions to the plate 10.

As the plates 10 and 13 are similar, I will limit my description to one of them.

Referring to plate 10 for illustration, 14 represents a series of pins or projections secured to that surface of said plate which is adjacent to the insulating material when said plate is in proper position on the machine.

15 represent the line wires, which are adapted to be connected with a source of electricity and connected to the machine by binding-screws 16 16, carried by the said plates 10 and 13. Connected to said bindingscrews, but insulated from them, are the terminals of an electric resistance, which I prefer to form of iine wire-such as 17having high resistance and low capacity. The Wire 17 is bent in a zigzag direction and is distributed over as much of the surface of the heating-plates as it can be made to cover without projecting beyond the edges thereof.

If the plates 10 and 13 be made of material capable of acting as electrical insulation, the wire 17 may be bare and placed in direct contact therewith, so that when the resistance is placed in circuit the resistance Willimpart its ICO heat to the plates very directly; but if said plates be of metal capable of conducting current it will be necessary to proceed about as follows:

1n order to hold the resistance 17 in proper position, as shown, they are coated with a film of porcelain, as is also the surface of the plates upon which they are placed, which ilin is preferably applied while the porcelain is in a liquid state. The film will afterward harden, holding, as above stated, the resistance properly in position.

1S represents the coating' of porcelain or any suitable insulation. (See Fig. 4.) The pins 14 are shown projecting above the coating of porcelain and into the sheet of asbestus, thus securely locking the whole structure together.

By the foregoing description it will be seen that the resistance-Wire 17 is fully insulated from proper portions of the press by the coating of porcelain, and that by the function of the asbestus the heat imparted to the plate is confined to the saine in a great measure q and prevented from effecting the other contiguous parts.

A therinometer-such as 19is attached to the upper movable heating section of the press, passing through the parts 11, 12 and 13 (see dotted lines in Figs. 1 and 2) for the purpose of indicating the temperature of the plate 13, and as the pressure and quantity of of current supplied to both upper and lower sections should be about the saine in practice by ascertaining the temperature of the plate 13 the temperature of the plate 10 can be approximated thereby.

ln order to heat both plates 10 and 13 simultaneously, it is necessary to connect the resistance of both plates to a source of electricity, which may be done in any suitable manner known to persons skilled in electrical work.

That I claim is- 1. As an improvement in hand-stamps, the combination, with a base or backing plate and a contact-plate carried thereby, of electric resistance-Wires located adjacent to said contact-plate, a non-conducting film disposed over said resistance, a heat-insulating sheet disposed between the film and the base or backing plate, and pins or projections carried by the contact-plate and projecting through the film and into the heat-insulating sheet, substantially as and for the purpose set forth.

2. As an ilnproveinentin hand-stamps, the combination, with a base or backing plate and a contact-plate carried thereby, of electrical resistance located at the back of the contact-plate and insulated from the base or backing plate, and inwardly-projecting pins or studs located between the plates and adapted to retain the latter in their proper relative positions, substantially as and for the purpose set forth.

3. The combination of stationary and movable plates 10 and 13, electric resistance-Wires 17, carried by said plates, porcelain located on said wires in the form of a film, pins or projections 1l, carried by said plates and projecting through said film of porcelain, sheets of asbestus or other heat-insulating material interposed between said film of porcelain and other parts adjacent thereto, and a thermometer located upon one of said plates, substantially as set forth.

In testimony whereof Iaflix my signature in presence of two witnesses.

JOHN BARNEY VENKER. lVitnesses:

ED. E. LoNeAN, C. F. KELLER. 

